In general most of electric cars which are driven with electric power are designed with an electromagnetic brake. More specifically, they are running by means of the transmission wheels which are driven by the transmission mechanism driven with electric power supplied from the battery. Notwithstanding, once the power source of an electric car is switched off, the electromagnetic brake will lock up the wheels as a result of power being turned off whereby the electric car is not allowed to move. The most often way of moving an electric car with power off lies in providing small amount of current passing through the electromagnetic brake allowing the release of the wheels from the electromagnetic brake. Nevertheless, because the motor, chain, and gear of the transmission mechanism remain engaged with the wheels, a considerable amount of resistance still exists resulting in difficult moving. For solving the problem, the optimal way is to mount a clutch on the transmission mechanism allowing for the disengagement of the transmission shaft from the wheels once the power source of an electric car is switched off whereby the wheels will become disengaged allowing the car to be moved by pushing. Notwithstanding, all the kinds of clutches at present are not suitable for an electric car. Referring to FIG. 1A and 1B, these two jaw type clutches are mounted in the intermediate portion of the transmission shaft but they are suitable for engagement and disengagement between the shafts. In general these two type clutches are usually mounted within a car while a complex mechanism is needed for the control of the clutch engagement or disengagement whereby the transmission mechanism can not be constructed in a simple manner.